Réponses

2013-04-10T19:15:24+02:00
1. A= (4x+3)(2x-1)-(4x+3)^2
= 8x^2 -4x +6x -3 -[ (4x)^2 +3^2 +2(4x)(3) ]
= 8x^2 +2x -3 -16^2 -9 -24x
= 8x^2 -22x -12

2. A= (4x+3)[(2x-1)-(4x+3)]
= (4x+3)(2x -1 -4x -3)
= (4x+3)(-2x-4)

3. pour x=-2
A= (4x+3)(-2x-4)
= [4(-2) + 3][-2(-2) - 4]
= (-8+3)(4-4)
= (-5)(0)
= 0

4. (4x+3)(-2x-4) = 0
4x+3 = 0 ou -2x-4 = 0
4x = -3 ou -4 = 2x
x = -3/4 ou -4/2 = x
x = -3/4 ou x = -2

^ = puissance